Minnesota paleontology and geology, National Park Service paleontology, the Mesozoic, and occasional distractions

Sunday, May 7, 2017

Sauropods, three-for-one

Three new sauropod species were published this week, although technically speaking all three are based on fossils that have been mentioned in the literature previously. This is just how things work in paleontology. Even if you know you have something new, it may be years or even decades for a description to surface. The three sauropods of the week cover three continents, two epochs, and three lineages. In a slight upset none of them are South American titanosaurs. Instead, they are diplodocid Galeamopus pabsti from the Upper Jurassic Morrison Formation of the United States, titanosaur Tengrisaurus starkovi from the Lower Cretaceous Murtoi Formation of Russia, and brachiosaurid Vouivria damparisensis from the Upper Jurassic Calcaires de Clerval Formation of France.

Galeamopus pabsti

Genus and species: Galeamopus is an existing genus, named in Tschopp et al. (2015), and the name is a multi-layered play on words. It translates as "need helmet", which both refers to the fragile braincase of the type and plays on "Wil-helm", or "William", for both William Utterback (who found the type) and William Holland (who initially described it). "pabsti" honors Dr. Ben Pabst, who discovered the type specimen of the new species and helped to prepare and mount it.
Citation: Tschopp, E. and O. Mateus. 2017. Osteology of Galeamopus pabsti
sp. nov. (Sauropoda: Diplodocidae), with implications for neurocentral
closure timing, and the cervico-dorsal transition in diplodocids. PeerJ 5:e3179.
Stratigraphy and geography: Morrison Formation (Kimmeridgian–Tithonian, Upper Jurassic), Howe-Scott Quarry in the Bighorn Mountains, Wyoming, United States, for the type specimen; a referred specimen is from Garden Park, Colorado.
Holotype: Sauriermuseum Aathal (SMA) 0011, most of a skeleton in front of the tail

SMA 0011 was previously described in Tschopp et al. (2015), the paper that named Galeamopus for "Diplodocus" hayi but which is better known as "the paper that resurrected Brontosaurus". It is joined in G. pabsti by a skull in the Smithsonian collections from Colorado (USNM 2673). Some of you are probably wondering if another Morrison diplodocid is warranted. It may not be immediately apparent from my history at Thescelosaurus and "The Compact Thescelosaurus", but I am neither a splitter nor a lumper; I'm an archivist who knows just enough to be dangerous. As I've gotten older, I've come to appreciate variation and other subtleties. A hundred years from now, if people are still doing paleontology, perhaps there will be enough of a sample size for Morrison diplodocids to permit a deep, detailed look at variation across the Morrison in time and space. Tschopp and Mateus found 14 diagnostic features for G. pabsti, spread throughout the skeleton. For now, I'm content to let history run its course.

Tengrisaurus starkovi

Genus and species: Tengrisaurus means "Tengri's lizard", Tengri being one of the names of the chief deity in the pre-Buddhist/Christian/Islamic Turkic–Mongolian religion. "starkovi" honors Alexey Starkov for his involvement in paleontology of the Transbaikal region.
Citation: Averianov, A., and P. Skutschas. 2017. A new lithostrotian titanosaur
(Dinosauria, Sauropoda) from the Early Cretaceous of Transbaikalia,
Russia. Biological Communications 62(1):6–18.
Stratigraphy and geology: Murtoi Formation (Barremian–Aptian, Lower Cretaceous), Mogoito in Buryatia, Russia
Holotype: Paleoherpetological Collection of the Zoological Institute, Russian Academy of Sciences (ZIN PH) 7/13, an incomplete anterior tail vertebra. ZIN PH 14/13 and 8/13, two additional tail vertebrae found within a few meters of the type, have also been assigned to this species and may belong to the type individual.

The tail vertebrae included in Tengrisaurus were first mentioned in print as far back as 1992 in the case of ZIN PH 8/13 (Nesov and Starkov 1992; Nesov 1995). Averianov and Skutschas's phylogenetic analysis places Tengrisaurus within Lithostrotia, the part of Titanosauria where the members sometimes have armor. Interestingly, Nesov and Starkov (1992) reported dinosaurian armor from the Mogoito site, but the two specimens could not be found by Averianov and Skutschas. Should the identification of Tengrisaurus as a lithostrotian be accurate, it would be one of the earliest known members, and for that matter one of the earliest known titanosaurs. The Murtoi Formation is dated as Barremian to Aptian, and most of the other named early titanosaurs are Aptian or Albian. The only real outlier is Triunfosaurus, which lived somewhen in the first half of the Early Cretaceous.

Vouivria damparisensis

Genus and species: "Vouivria" is a reference to "vouivre", a serpentine flying reptile with a dragon's head, etymologically related to the "wyrven" and the English "viper". "damparisensis" refers to Damparis, where the type specimen was found.
Citation: Mannion, P. D., R. Allain, and O. Moine. 2017. The earliest known titanosauriform sauropod dinosaur and the evolution of Brachiosauridae. PeerJ 5:e3217.
Stratigraphy and geology: Calcaires de Clerval Formation (upper middle–lower upper Oxfordian, Upper Jurassic), Damparis, Franche-Comté, France
Holotype: Muséum National d'Histoire Naturelle (MNHN).F.1934.6 DAM 1 to 42, an associated partial skeleton including teeth, several partial neck and back vertebrae, a partial sacrum, a tail vertebra, most of the shoulders, arms, and hands, part of the pelvis, legs, and feet, and ribs

Vouivria comes at the end of a chain of inexplicable taxonomic decisions, going all the way back to Richard Owen in 1875 blessing the world with Bothriospondylus (Mannion 2010; Mannion et al. 2017). "What is Bothriospondylus?", you may ask. Bothriospondylus is many things. It is a quaint Victorian relic, a couple of rungs lower than Ornithopsis on the fame (or notoriety) scale and a couple of rungs above Eucerospondylus. It is an indeterminate Upper Jurassic English sauropod. It is one of life's small frustrations, like discovering that restaurant you liked is closed for good, or running into a door frame in the dark. For reasons that presumably made sense at the time, it acquired several species to go with the type species, B. suffossus. One of these was Richard Lydekker's Bothriospondylus madagascariensis, logically enough from Madagascar. Why put it in Bothriospondylus? I guess you had to be there. Lydekker seems to have preferred creating new species in existing genera over creating new genera. (He was also the paleontologist most responsible for Iguanodon being stuffed with anything remotely iguanodontian.) In 1934 a partial skeleton of a sauropod was found at Damparis, France. Albert-Félix de Lapparent (1943) made the curious decision to assign it to Bothriospondylus madagascariensis, from which we got "French Bothriospondylus" (most later reviewers didn't keep the "madagascariensis" part but kept "Bothriospondylus"). (Perhaps this should have been seen as ominous. He would later name species based on batches of fossils collected at multiple locations scattered across North Africa, such as Elaphrosaurus iguidiensis and Inosaurus tedreftensis.) In the end, Vouivria turns out to be what it was long suggested to be: a brachiosaurid. At this time, it is just barely (in geologic terms) the earliest named brachiosaurid.

Figure 40 from Mannion et al. (2017). The original heading and caption are "Time-calibrated phylogenetic tree, showing geographic distribution of basal Macronaria. Brachiosauridae is resolved after the a posteriori deletion of Abydosaurus in TNT. Silhouette of Giraffatitan drawn by Matthew Wedel and available at Phylopic under a Creative Commons Attribution 3.0 Unported license (https://creativecommons.org/licenses/by/3.0/legalcode). Global palaeogeographic reconstructions from Fossilworks (http://fossilworks.org/) showing the distribution of Late Jurassic and Early Cretaceous brachiosaurids." Note that the red stars in Africa's Early Cretaceous represent unnamed species, so they don't show up in the chart.

References

If you're downloading on any kind of slow connection, be aware that the pdf version of Tschopp and Mateus (2017) is 94 mb, and Mannion et al. (2017) tips the scales at 124 mb.

Averianov, A., and P. Skutschas. 2017. A new lithostrotian titanosaur (Dinosauria, Sauropoda) from the Early Cretaceous of Transbaikalia, Russia. Biological Communications 62(1):6–18.

Mannion, P. D. 2010. A revision of the
sauropod dinosaur genus 'Bothriospondylus' with a redescription of the
type material of the middle Jurassic form 'B. madagascariensis'. Palaeontology 53(2):277–296.